The science dealing with mental processes, both normal and abnormal, and their effects upon behavior.

There are two main approaches to the study: introspective, looking inward or self-examination of one's own mental processes; and objective studying of the minds of others.

A branch of mental behavior that is concerned with the study of thinking processes that are involved in perceptions, learning, memory, and reasoning: As a part of her educational studies to become a teacher, Mary had to take a course involving cognitive psychology, in order to learn how to present her lessons to students in the most effective manner.

1. Mental science applied to certain problems found in industry; dealing primarily with personnel selection, training, and the mental health of workers.
2. The branch of human behavior that is concerned with the efficient management of an industrial labor force and especially with problems encountered by workers in a mechanized environment: "Industrial psychology came into existence in the late 19th and early 20th centuries, at a time when industrial production was expanding, new types of labor and common occupations were emerging, and greater demands were being made on individuals."